Influencer marketing is a partnership between a brand and online creators (influencers) who have a community that trusts them and real influence over its decisions. An influencer is someone who regularly posts content on social media and can recommend a product in a way that feels natural to their audience. In a campaign, the creator presents your brand to their followers, and you gain reach and credibility that are hard to buy with regular advertising.
In practice, that covers campaign strategy, creator selection, the creative brief, contracts, getting the content live and measuring results. What matters is how well the creator fits your brand and goal, not just how big their reach is.